Tell me your: "move loss average" at the bottom.
That's basically how much your graphics lag. It has nothing to do with internet connection though.

Notes:
-only works on firefox and chrome
-If you see Error #2048 at the bottom then refresh the browser.
-Use arrow keys to move
-players don't disappear when they leave. refresh the browser if there are too many people.
-need flash player installed

Please give feedback.

Edit: gah should work now I forgot to take it out of sandbox mode. That's why people coundn't connect.